Sexual reproduction entails the union of two gonads to form a zygote.
Males produce sperm and females produce eggs.
The presence of the Y chromosome guarantees the development of male secondary sex organs.
The mechanism that keeps the testes cooler than the body's core temperature is called descent of the testes.
The scrotum contains the testes and spermatic cords.
Sperm travels to the ampulla of the ductus deferens before reaching the spermatic cord.
Nurse cells secrete inhibin, which regulates the rate of sperm production.
Testosterone stimulates development of the secondary sex characteristics, spermatogenesis, and libido.
Erectile dysfunction prevents ejaculation in most cases.
At early puberty, follicle stimulating hormone (FSH) and luteinizing hormone (LH) stimulate enlargement of the testes.
Spermiogenesis is the last stage of meiosis.
Sperm make up just 10% of semen volume.
Only germ cells undergo meiosis, which produces four haploid (n) cells with 23 chromosomes each.
Sympathetic nerve fibers trigger the secretion of nitric oxide, which dialtes the deep arteries allowing
The first haploid (n) stage of spermatogenesis is prophase II.
Myotonia of skeletal muscles is characteristics of the excitement phase and refractory period.
Which of the following is generally accepted as a secondary sex characteristic?
The enlargement of the breasts
Which of the following are female primary sex characteristics?
Which of the following is a female secondary sex organ?
Gonads begin to develop _________ weeks after fertilization.
5 to 6
Whether an orgasm will be genetically male or female is determines by
The gene that codes for the testis-determining factor (TDF) is found in or on the
The penis is homologous to the
The _________ is the gonad and the _________ is the gamete.
Descent of the testes is stimulated by the
presence of testosterone
The _________ is an example of the female external genitalia.
The __________ is the small, bilateral organ found lateral to the membranous urethra.
The golf-ball sized structure found inferior to the urinary bladder, and surrounding the most proximal portion of the urethra, is called the
The __________ is the site of sperm maturation and storage.
The deep region of the penis, surrounding the urethra, that engorges with blood during an erection is known as the
Which of the following is the correct pathway of sperm cells from their formation to ejaculation?
Seminiferous tubule, rete testis, epididymis, ejaculatory duct, urethra, ductus deferens
When it is cold, the _________ contracts and draws the testes closer to the closer to the body to keep them warm.
The countercurrent heat exchanger that prevents arterial blood from overheating the testes is the
pampiniform plexus of veins
Which of the following is true regarding the blood-testis barrier?
It prevents antibodies in the blood from getting to the germ cells.
By volume, most of the semen is produced in the
Which of the are not found in or around the seminiferous tubules?
Corpus cavernosum cells
The penile urethra is enclosed by the
Men have only one
Why would an enlarged prostate interfere with urination?
It compresses the urethra
The penis is innervated by the _________ nerve.
Which of the following does not play a role in thermoregulation of the testes?
The bulbosponiosus muscle
When do the testes start secreting testosterone?
In the first trimester of fetal development
Which of the following hormones directly stimulates the development of male secondary sex characteristics?
Which of the following is an androgen?
__________ stimulates the interstitial cells of the testes to secrete __________.
Luteinizing hormone (LH); testosterone
Which hormone suppresses spermatogenesis without affecting testosterone secretion?
The _________ has/have no androgen receptors and do/does not respond to it.
Which of the following is inhibited by testosterone?
Gonadotropin-releasing hormone (GnRH) secretion
Changes called male climacteric are a consequence of a(n)
decreased secretions of testosterone
The haploid (n) result meiosis I is called a
In the process of spermiogenesis, __________ become ___________ .
In meiosis, each parent cell produces
four haploid (n) cells
The process of spermatogenesis begins with a __________ and ends with four __________.
germ cell; gametes
At the end of meiosis I there are _________, whereas at the end of meiosis II there is/are __________.
two haploid (n) cells; four haploid (n) cells
Which of the following is the most important role of meiosis in sexual reproduction?
It prevents the chromosome number from doubling in each generation.
At what stage does a developing sperm cell begin to grow a tail?
Sperm cells get energy to power their movement from _________, which is contributed by the __________.
fructose; seminal vesicles
Male infertility (sterility) refers to
the inability to fertilize an egg
The acrosome contains enzymes used to
penetrate barriers surrounding the ovum
_________ have 46 chromosomes, whereas __________ have 23.
Primary spermatocytes; spermatids
A sperm count any lower than _________ million sperm per mL of semen is usually associated with infertility (sterility).
20 to 25
Dilation of the _________ causes the lacunae to fill with blood and the penis to become erect.
The orgasm-emission phase of the male sexual response is stimulated by
efferent sympathetic signals from the lumbar region of the spinal cord
Which of the following explains the neural mechanism of an erection?
It is an autonomic reflex mediated predominantly by parasympathetic nerve fibers
Heart rate, blood pressure, and respiratory rate peak during the
Sildenafil (Viagra) prolongs erection by
inhibiting degradation of cGMP
Which of the following are changes in the male body that results from puberty?
Deepening of the voice, gain in muscle mass, growth of the scrotum and penis, acne
Which of the following is not a function of the nurse cells?
They secrete testosterone
Genetic males are XY and genetic females are XX.
In the female fetus, the absence of testosterone results in the development of the external genitalia into clitoris, labia minora, and labia majora.
The uterus is a thick muscular chamber inferior to the urinary bladder.
The vagina has no glands but it is moistened by mucus from glands in the cervical canal.
Although two breast cancer genes are known, most cases are nonhereditary.
Inhibin modulates the secretion of LH.
The number of ovarian follicles declines with age, leading to a reduction of estrogen levels.
The ovarian cycle typically lasts about 28 days, with day 1 considered to be the first day ovulation.
Most primary oocytes undergo atresia during climacteric.
The proliferative phase of the uterus is driven by estrogen from the ovaries.
In the excitement phase, the uterus rises from its forward-tilted (anteverted) position.
Unlike men, women lack a refractory period and may experience successive orgasms.
Human chorionic gonadotroping (HCG) stimulates the corpus luteum to grow and secrete estrogen and progesterone.
Progesterone stimulates uterine contractions.
Prolactin is secreted during pregnancy to stimulate milk synthesis so that milk will be available by the time the infant is born.
Oxytocin stimulates contraction of myoepithelial cell of the mammary acini.
Which of the following is a part of the internal female genitalia?
In which structure does fertilization usually occur?
Which of the following structures is composed of a theca folliculi, granulosa cells, a zona pellucida, and a secondary oocyte?
What structure leads from each ovary to the uterus?
Which uterine layer is composed of a simple columnar epithelium containing tubular glands?
Which of the following is not a component of the vulva?
In the prementrual phase of the menstrual cycle, which arteries rhythmically constrict and dilate causing endometrial ischemia?
After puberty, which epithelium lines the vagina?
Stratified squamous epithelium
Where does an embryo usually attach to its mother?
To the endometrium
What provides most of the natural lubrication during female sexual excitement?
Greater vestibular glands
The nonpregnant uterine wall consists mostly of
Which of these is not found in the vestibule?
__________ are found in both male and female external genitalia, but the __________ is/are only found in the female.
Corpora cavernosa; vestibular bulbs
When do mammary glands primarily develop within the breasts?
What determines breast size?
The amount of adipose tissue
Where are follicles located?
Cortex of the ovary
What is the earliest sign of puberty in girls?
The onset of breast development
Which of the following is considered a "feminizing hormone"?
Which hormone acts primarily on the uterus?
The appearance of pubic and axillary hair is characteristic of which stage of puberty?
What is the midlife change in estrogen and progesterone levels referred to as?
What is the cessation of menstruation referred to as?
During climacteric, what can cause hot flashes?
Vasodilation of cutaneous arteries
What does the term "menstrual cycle" specifically refer to?
The cyclic changes in the uterus determined by shifting hormonal changes
What is an ovulated egg more technically referred to as?
A secondary oocyte
Which stage of meiosis is an ovulated egg in?
When does an ovum finish meiosis?
Most ovulation home test kits measure a surge of which hormone?
In ovulation, after expelling the oocyte the follicle becomes a _________ and secretes __________.
corpus luteum; estrogen and progesterone
What is a follicle composed of?
An oocyte enclosed in follicular or granulosa cells
Which follicle stage is characterized by the development of a corona radiata?
When does oogenesis begin?
During embryonic development
In the adult ovary, more than 90% of the follicles are found as
During the follicular phase, granulosa cells secrete _________, which stimulates secretion of _________.
Which of these blood hormone levels reaches its maximum during the luteal phase?
What hormone(s) inhibit(s) the secretion of FSH and LH during the female sexual cycle?
Estradiol and progesterone
What do lutein cells develop from?
The theca interna
Which phase of the mentrual cycle is the one associated with menstrual cramps?
Which of the following occurs during the proliferative phase of the menstrual cycle?
Several follicles are developing an antrum
The ________ sometimes expels copious fluid similar to prostatic fluid, which constitutes the female ejaculate.
During the plateau phase of the sexual response, the glans and clitoris swell as the deep arteries dilate and the ________ engorge with blood.
In early pregnancy, what hormone stimulates growth of the corpus luteum?
Human chorionic gonadotropin
During ________, the uterus is tented (erected) and the cervix is withdrawn from the vagina. Typically, the clitoris is engorged and the labia are bright red to violet due to hyperemia.
Pregnancy kits test for the presence of what hormone?
Human chorionic gonadotropin
Between weeks 3 and 8 of development, a developing individual is considered a(n)
Contraceptive pills mimic the ________ feedback effect of ________.
negative; estrogens and progesterone
Which form of estrogen is the most potent in pregnancy?
Which of the following provides fetal nutrition and secretes hormones that regulate pregnancy and fetal development?
What is the longest stage of labor?
The dilation stage
Milk ejection occurs as a result of stimulation of nerve endings in the ________, which leads to the release of ________from the pituitary.
nipple and areola; oxytocin
Why is breast milk superior to cow's milk for an infant?
Cow's milk has too much protein and minerals in it.
What is the infant's only source of nutrition during the first 2-3 days postpartum?
The medial pole of the ovary is attached to the uterus by which ligament?
The anterior margin of the ovary is anchored by a peritoneal fold called the
The ovary receives blood from which artery/arteries?
Ovarian and uterine
During climacteric, women secrete
less estrogen and progesterone
Which of the following is true of the female sexual response?
Women do not have a refractory period and may quickly experience additional orgasms.
Why do pregnant women often have heartburn?
As the uterus enlarges it pushes upward on the stomach, causing gastric reflux.
Women with morning sickness tend to prefer spicy and pungent foods.
"False labor" is result of what type of contractions?
When an infant suckles at its mother's breast, milk moves through the breast structures in what order?
Acinus > lactiferous duct > lactiferous sinus > nipple
How is colostrum different than breast milk?
It has one-third less fat.
Which of the following is not a benefit of breast feeding?
It prevents colonization of the neonatal intestine with beneficial bacteria.
Sperm must travel to the distal end of the uterine tube to encounter the egg before it dies.
The slow block referes to the mechanism that prevents fertilization of another egg when one is already pregnant.
The fertilization membrane is the endometrial tissue that receives the conceptus.
Cleavage results in daughter cells containing half the number of chromosomes of the parent cell.
During implantation, the embryoblast undergoes gastrulation.
The embryonic stage extends from 16 days through the end of week 8.
The chorion forms the fetal part of the placenta.
The placenta begins to form after week 8.
Trophoblastic nutrition refers to the nutrition of the conceptus before it implants.
Neonatal immunity depends on IgG and IgA acquired through the placenta and colostrum, respectively.
To some extent, the heat loss of the neonate is compensated for by the thermal insulation provided by brown fat.
Inadequate liver function is the most common reason that premature infants suffer from multiple dysfunctions.
Teratogens usually do not cause congenital anomalies.
Senescence begins different ages and progresses at different rates in different organ systems.
Life expectancy has steadily increased in the last century, whereas life span has not.
A person in his or her 90's can increase muscle strength by two or three times with 40 minutes of isometric exercise per week.
Which of the following lists the stages or structures of prenatal development in the correct order?
Zygote, cleavage, morula, blastocyst, embryo, fetus
The process that makes it possible for sperm to penetrate the eggs is called
In the slow block to polyspermy, sperm penetration release an inflow of _________, which in turn stimulates the __________.
Ca2+; cortical reaction
In the fast block to polyspermy, binding of sperm opens up __________ channels, which depolarizes the egg membrane and __________.
Na+; prevents the entrance of any more sperm
Regarding fertilization, which of the following events happens first?
The acrosomal reaction
The optimal "window of opportunity" to conceive a child is
a few days before ovulation to less than a day after
The spheroidal stage of early prenatal development with about 16 to 64 cells is called a(n)
Twins produced when a single egg is fertilized are called __________ twins. Twins produced from two eggs ovulated at the same time are called _________ twins.
In the blastocyst, the trophoblast will become________, whereas the embryoblast will become __________.
part of the placenta; the embryo
Primary germ layers are formed during
Mesenchyme gives rise to _________.
muscle, bone, and blood
During implantation, the trophoblast divides into a deep layer called the ________, which is composed of individual cells.
By the time the conceptus arrives in the uterus, it consists of at least ________ or more cells.
During implantation, the trophoblast divides into a superficial layer called the ________, which is composed of a multinucleate mass of cytoplasm.
Out of the 300 million ejaculated sperm, only about ________ reach the vicinity of the egg.
200 to 300
Prior to ejaculation, __________ in the plasma membrane of the sperm prevents premature release of __________.
cholesterol; acrosomal enzymes
Which of the following is not a derivative of ectoderm?
The first body cavity is called the
By the end of 8 weeks, the individual is considered a fetus because
all of the organ systems are present
The __________ completely encloses the embryo and provides it with a stable environment.
The _________ encloses all the rest of the membranes and the embryo.
The _________ is an embryonic membrane that serves as the origin of the first blood and germ cells.
As it implants, the concepts is nourished by means of
The ________ begins to develop about 11 days after conception, and is the sole source of fetal nutrition from the end of week 12 until birth.
In fetal circulation, the ________ bypasses the liver and the _________ bypasses the lungs.
ductus venosus; ductus arteriosus
In fetal circulation, blood bypasses the lung by flowing through the
foramen ovale and ductus arteriosus
Which of the following major events of prenatal development happens first?
The central nervous system begins to form
Oxygenated blood reaches the fetus through the
Which of the following is not considered an embryonic membrane?
________ pass(es) from the maternal blood to the fetal blood. Fetal ________ pass(es) the other way.
Oxygen and nutrients; wastes
The digital rays of a fetus give rise to
fingers and toes
The first 6 weeks of postpartum life constitute the _______ period.
The fossa ovalis is a remnant of the ________ of the fetus.
During birth, an infant is normally stimulated to breathe by
CO2 accumulating in the baby's blood
Which of the following organ systems shows the greatest anatomical change in the transitional period after birth?
Infant respiratory distress syndrome (IRDS) is caused by
deficiency of pulmonary surfactant
Which of the following organ systems faces the greatness physiological challenge in the transitional period after birth?
A teratogen is most likely to cause
a deformity of the limbs
Which of the following does not have potentially teratogenic effects?
Down syndrome (trisomy-21) results from
The most likely outcome of nondisjunction is the production of a gamete receiving
Only autosomal trisomes involving chromosomes 13, 18, and 21 are survivable. Why would this be?
These are relatively gene-poor chromosomes
Urine retention is a greater problem for elderly men than for elderly women because men
can develop benign prostatic hyperplasia
Which of the following is not a reason muscular weakness tends to develop in old age?
The myocytes of aged muscle no longer synthesize myosin.
Older people may require lower drug doses than younger people because
they have lower rates of renal clearance
Which of the following statements is true regarding telomeres?
Telomeres are DNA segments at each end of a chromosome.
The observation that there is a limit to how many times a cell can divide is the basis for the ________ theory of senescence.
Which of the following systems shows the least overall senescence?
Senescence of the immune system makes older people more susceptible to cancer and infectious disease because of a decline in
antigen-presenting cells and helper T cells
Which of the following is not a known benefit of regular exercise?
Prolonged life expectancy
Which of the following is not a known cause of congenital anomalies?
Smoking during lactation
The fetus deposits fat in its subcutaneous tissue in the 7th month of gestation.